With the development of the 3rd-generation (3rd-generation, 3G) mobile communications technologies and long term evolution (Long Term Evolution, LTE) technology, wireless-fidelity (Wireless-Fidelity, Wi-Fi) devices, as portable devices that allow a plurality of Wi-Fi devices to share the uplink bandwidth of an LTE network or a 3G network, are increasingly popular among users. A Wi-Fi device has an in-built LTE/3G chip and Wi-Fi chip. In the uplink, it accesses the Internet via a wireless network such as the LTE network and the 3G network. In the downlink, it provides Internet access for other Wi-Fi devices via a Wi-Fi network complying with 802.11b/g/n. Mainstream Wi-Fi devices at present generally allow 10 or more Wi-Fi devices to access the LTE network or 3G network via Wi-Fi simultaneously. These Wi-Fi devices may be notebook computers, tablets, mobile phones, and the like.
The current highest downlink rate of the LTE network is capable of reaching 150 Mbps, around 10-20 times higher than the 3G network rate. To match the high rate of the LTE network and enable Wi-Fi users to surf the Internet at a higher rate, the latest Wi-Fi devices in the industry have used the Wi-Fi multiple-input multiple-output (Multiple-Input Single-Output, MIMO) technology that may increase the maximum rate of a Wi-Fi network to more than 100 Mbps by using multi-path radio frequency and antennas.
In the prior art, the Wi-Fi work mode is set to a MIMO mode when the Wi-Fi device is started, to meet the requirement of the Wi-Fi access rate. However, the requirement of enabling a plurality of radio frequency paths in the MIMO mode results in a problem of relatively high power consumption.